Cushioning device



Sept. 22, 1936. s. c. SMITH 2,055,242

CUSHIONING DEVICE Filed May 6, 1929 INVENTOR dcdmi'f/z ATTORNEYG Patented Sept. 22, 1936 CUSMONING DEVICE Application May 6. 192a, Serial. No. stones 9 Claims.

My invention relates to improvements in cushioning devices, and it consists in the combinations, constructions, and arrangements herein described and claimed.

An object of my invention is to provide a cushioning device which may be attached to land vehicles, but which is especially adapted to be used as a landing strut for airplanes or the like.

A further object of my invention is to provide m a device of the type described which will not rapidly rebound the load, but will rebound the load very slowly.

A further object of my invention is to provide a device of the type described which is exceedingly simple inconstruction, durable, and efficient for the purpose intended.

Other objects and advantages will appear in. the following specification, and the novel features of the invention will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawing, forming part of this application, in which Figure 1 is a front elevation of my device as applied to an airplane,

Figure 2 is a longitudinal sectional view of my device,

Figure 3 is a longitudinal sectional view of a modified form of my device,

Figure 4 is a section along the line t t of Figure 3, I

Figure 5 is a longitudinal sectional view of another modified form of my device,

Figure 6 is a section along the line fi -d of 35 Figure 5, and

Figure Tie a section along the line i-l of Figure 2.

In carrying out my invention, I make use of an airplane l having an axle 2 pivotally carried thereby. A landing wheel it is rotatably mounted upon the axle 2. Bracing members t and 5 ex-- tend outwardly from the fuselage oi the airplane and have their ends connected at ii.

I provide a cushioning device having an outer as sleeve or casing l and an inner sleeve or casing d which is slidably disposed within the outer casing and provided with slits 80', which provide a plurality of resilient friction shoes-8b as shown in Figure 7. A core 9 is disposed within so the inner sleeve 8 and extends a short distance from the inner edge of the slits. A movable block it is disposed in the outer sleeve l and has a reduced portion disposed in the inner sleeve.

A compression spring H is disposed in the outer 5t sleeve 1 adjacent the block it. An expanding member [2 is disposed between the movable block ii] and the core 9 in the inner sleeve 8. The outer sleeve l is pivotally secured to the axle 2 at It and the inner sleeve ii is pivotally secured to the braces i and 5 at the point t. It ii is obvious that the device may be secured in the reverse order if so desired.

From the foregoing description of the various parts of the device, the operation thereof may be readily understood. In Figure 1 the landing id wheel 3 and the axle 2 are shown in dotted lines in the flying position and in solid lines in landing position. As the wheel and the axle are moved into the landing position, the outer sleeve l is moved upwardly. As the outer sleeve '6 is moved upwardly, the spring is compressed, thus forcing the movable block it against the expanding member I2, which is made of any suitable flexible material, such as rubber. The member It will thus expand and force the friction shoe to into close engagement with the wall of the outer sleeve '5, and as movement takes place between the outer sleeve '5 and the friction shoes 8b, part of the force exerted to move the outer sleeve i upwardly is destroyed by friction.

The greater the upward movement of the outer sleeve 1, the greater will be the frictional contact of the friction shoes 8b with the inner wall of the sleeve 1. The contact portion of the shoes may be covered with brake lining if it is so desired.

A part of the thrust is received by the spring M and is stored up in the spring ii in the form of potential energy. This energy returns the cushion back to its normal position. However, 35 the greater the thrust, the greater will be the compression of the spring ii tending to compress the expanding member 62. As the sleeve 1 moves downwardly to the flying position, the friction members to retain the frictional contact as long as there is tension upon the spring. The friction increases directly proportional to the compression movement of the device and also decreases directly proportional to the extension movement.

The amount of friction to be destroyed can be varied as desired by varying the resiliency of the expanding member 112, or by varying its length and diameter.

When the brake and the spring are properly connected in any desired ratio, the shock is partly destroyed by the friction of the brake shoes and partly absorbed by the spring on the bound, and on the rebound the potential energy stored in the spring in the first instance is partly exhausted by the brake shoes upon its returning to its normal position. The acme of perfection is reached when the movable part comes to a state of rest at the end of the first rebound.

The greater the compressive force or energy imparted to the movable parts of the invention, the greater is the force applied to the destruction thereof, and the reverse is true of the expansion of such parts. It is also to be noted that the amount of pressure exerted by the brake shoes is dependent upon the energy in the spring connected therewith, and that the action of the brake shoes and the spring is always correlated. They are never separated and never act independently of each other.

The operation of the cushion is governed by certain laws. That relating to a coiled spring is that the force of the spring is in direct proportion to the distance it is compressecLand the one governing a brake is that the energy destroyed by friction is directly proportional to the pressure exerted to produce the friction. The result of a combination of these laws would be that the energy destroyed by the brake shoes is in direct proportion to the energy stored in the spring, and the energy stored in the spring is directly proportional to the distance through which the force acts on the spring. Therefore, the energy destroyed is in direct proportion to the amount of motion or distance moved, which is in turn direct- 1y proportional to the force of the shock received.

In the modified form shown in Figures 3 and 4 I have provided a pivot block [4 which is hollow, as at I5, and provided with a rounded edge l6. A plurality of actuating levers I! are disposed in engagement with the rounded end It at spacedapart positions, as shown in Figure 4. The levers are provided with contact portions l8 at one of their ends, their other ends extending inwardly and provided with V-shaped surfaces IS. The pivot block I 4 is disposed adjacent the core 9 and the levers I! are disposed in engagement with the block l0.

During the movement of the sleeve 1 with respect to the sleeve 8, the block In and its engagement with the adjacent ends of the levers l1 will tend to force these ends within the hollow portion I 5, thus pivoting the levers around the edge iii of the block I 4 and swinging the contact [8 outwardly, thus forcing the friction shoes into frictional contact with the inner wall of the sleeve 1. The variance of the movement of the sleeves I and 8 with respect to each other will vary the frictional-eontact of the shoes with the inner wall of the sleeve 1. A spring II will cooperate in the same manner as is shown in Figure 2. When the levers are swung about the end Hi, the V-shaped edges I9 of the levers are moved toward each other.

In the form shown in Figures 5 and 6, a plurality of friction blocks 20 which are substantially triangular in cross section are disposed adjacent each other in the inner sleeve so as to provide.

a circular formation. A spreading block 2| is conical shaped in general contour and has its conical-shaped end 22 disposed in the conicalshaped recess formed by the tapered walls 23 of the friction blocks 20.

The friction blocks 20 are disposed adjacent the core 9, while the block 2| is disposed in engagement with the movable block l0. As the sleeve I is moved with respect to the sleeve 8, the conical-shaped block 2| forces the friction blocks 20 outwardly, thus forcing the friction shoes 8b into frictional engagement with the inner wall of the sleeve 1. The greater the pressure applied to the friction blocks, the greater will be the frictional contact between the friction blocks and the inner wall of the sleeve 1, thus tending to check the movement of the sleeves with respect to each other.

I claim:

1. A device of the type described comprising an outer sleeve, an inner sleeve slidably disposed within the outer sleeve, said inner sleeve being slotted at one end thereof within the outer sleeve to provide resilient friction shoes, a member expansible in cross section upon longitudinal compression disposed wholly within the inner sleeve, and means for engaging said expansible member to force the latter into contact with said resilient shoes when the sleeves are moved relatively toward one another in one direction.

2. A device of the type described comprising an outer sleeve, an inner sleeve slidably disposed within the outer sleeve, said inner sleeve being slotted at one end thereof to provide resilient friction shoes, a core disposed within the inner sleeve, a movable block carried by the outer sleeve, and means disposed between the core and the block and adapted to be actuated by the rela-' tive movement of the core and the block toward each other for engaging the resilient'shoes and forcing them into frictional contact with the walls of the outer sleeve.

3. In a device of the type described, an outer sleeve, an inner sleeve, said inner sleeve being slotted at one end to constitute resilient shoes, a core carried by the inner sleeve, a movable block carried by the outer sleeve, said inner and outer sleeves being closed at their ends, a spring in said outer sleeve resting on the closed end of the sleeve and at the other on the block, and an expansible member disposed between the block and the core and adapted to be brought into engagement with the shoes during a relative movement of the block or core toward one another for forcing the shoes into frictional engagement with the interior walls of the outer sleeve.

4. In a device of the type described, an outer sleeve, an inner sleeve, said inner sleeve being slotted at one end to constitute resilient shoes,

a core carried by the inner sleeve, a movable block carried by the outer sleeve, said inner and outer sleeves being closed at their ends, a spring in said outer sleeve arranged to bear at one end on the closed end of the sleeve and at the other on the block, a pivot block disposed within the inner sleeve and having a rounded edge, and a plurality of actuating leverspin contact with said rounded edge, said levers being arranged to be engaged by said movable block to pivot the levers on the edge of said pivot block, whereby one end of said levers is brought into engagement with the shoes to force the latter into frictional engagement with the interior walls of the outer.

core causing the spreader block to force said friction blocks into engagement with said resilient shoes, whereby the latter frictionally engage the interior wall of the outer sleeve.

6. A shock absorbing strut comprising a cylinder having a closed end, a piston movable therein having bifurcated flexible end portions, a compressible expansible member in the end of the piston between the bifurcated end portions, a block movable in the cylinder engaging the expansible member and a spring positioned between the block and the closed end of the cylinder.

7. A shock absorbing strut comprising a cylinder, a piston movable therein having a bifurcated end, a member expansible in cross section cylinder and member.

8. A shock absorbing strut comprising 9. cylinder having one end closed, apiston movable therein having a bifurcated end, a member expansible in cross section upon longitudinal compression in the bifurcated end, a single block in the cylinder engaging the expansible member and a resilient compression member between the block and the closed end of the cylinder.

' 9. A shock absorbing strut comprising a cylinder having one end closed, a piston movable in the cylinder having bifurcated flexible end portions, a member expansible in cross section upon flongitudinal compression between the flexible end portions, a block movable in the cylinder engaging the expansible member and a resilient compression member in the cylinder between the block and the closed end of the cylinder.

STUYVESANT C. SMITH. 

